must use fabs() on doubles, not abs(), to avoid ambiguity

src/USER-MESO/fix_edpd_source.cpp

@@ -112,7 +112,7 @@ void FixEDPDSource::post_force(int vflag)
         drx = x[i][0] - center[0];
         dry = x[i][1] - center[1];
         drz = x[i][2] - center[2];
-        if(abs(drx) <= 0.5*dLx && abs(dry) <= 0.5*dLy && abs(drz) <= 0.5*dLz)
+        if(fabs(drx) <= 0.5*dLx && fabs(dry) <= 0.5*dLy && fabs(drz) <= 0.5*dLz)
           edpd_flux[i] += value*edpd_cv[i];
       }
     }

src/USER-MESO/fix_tdpd_source.cpp

@@ -112,7 +112,7 @@ void FixTDPDSource::post_force(int vflag)
         drx = x[i][0] - center[0];
         dry = x[i][1] - center[1];
         drz = x[i][2] - center[2];
-        if(abs(drx) <= 0.5*dLx && abs(dry) <= 0.5*dLy && abs(drz) <= 0.5*dLz)
+        if(fabs(drx) <= 0.5*dLx && fabs(dry) <= 0.5*dLy && fabs(drz) <= 0.5*dLz)
           cc_flux[i][cc_index-1] += value;
       }
     }